Neuromodulation

Patternable Gelatin Methacrylate/PEDOT/Polystyrene Sulfonate Microelectrode Coatings for Neuronal Recording

This manuscript addresses the need for new soft biomaterials that can be fabricated on the surface of microelectrodes to reduce the mechanical mismatch between biological tissues and electrodes and improve the performance at the neural interface. By electrochemical polymerization of poly(3,4-dioxythiophene) (PEDOT)/polystyrene sulfonate (PSS) through a gelatin methacrylate (GelMA) hydrogel, we demonstrate the synthesis of a conducting polymer hydrogel (CPH) to meet the performance criteria of bioelectrodes. The hybrid material can be photolithographically patterned and covalently attached to gold microelectrodes, forming an interpenetrating network, as confirmed by infrared spectroscopy. The GelMA/PEDOT/PSS coatings were found to be reversibly electroactive by cyclic voltammetry and had low impedance compared to bare gold and GelMA-coated microelectrodes. The CPH coatings showed impedance at levels similar to conventional PEDOT/PSS coatings at a frequency of 1000 Hz. CPH exhibited electrochemical stability over 1000 CV cycles, and its performance was maintained over 14 days. Biocompatibility of the CPH coatings was confirmed by primary hippocampal neuronal cultures via a neuronal viability assay. The CPH-coated microelectrode arrays (MEAs) successfully recorded neuronal activity from primary hippocampal neuronal cells. The CPH GelMA/PEDOT/PSS is a highly promising coating material to enhance microelectrode performance at the neural interface.

Carbon nanofiber-PEDOT composite films as novel microelectrode for neural interfaces and biosensing

A clear need exists for novel nanostructured materials that are capable to meet the performance criteria of a number of neuronal therapies including neural recording, stimulation and sensing of bioactive molecules at the electrode-tissue interface. By combining Poly (3,4-ethylenedioxythiophene) (PEDOT), with Carbon Nanofibers (CNFs), we demonstrate a versatile approach for the synthesis of a novel composite material PEDOT:CNF with remarkable electrochemical properties, combining low impedance, high surface area, high charge injection capability and reliable neurotransmitters monitoring using amperometric techniques. The oxidized CNFs were utilized as dopants of PEDOT to prepare the composite coatings through electrochemical deposition on neural microelectrodes arrays (MEA). The PEDOT:CNF modified microelectrodes demonstrated the low specific impedance of 1.28 MΩ μm² at 1 kHz and results in unrivalled charge injection limit of 10.03 mC/cm² when compared to other reported organic electrode nanomaterials. Furthermore, amperometric detection performances were determined for the neurotransmitters dopamine and serotonin, exhibiting linear concentration range from 0.1 to 9 μM and from 0.06 to 9 μM respectively, high sensitivities (44.54 pA/nM.μm² and 71.08 pA/nM.μm², respectively) and low detection limits (0.045 μM and 0.056 μM, respectively). Cell viability was investigated on PEDOT:CNF coated microelectrodes to show that the composite material does not advocate any cytotoxicity. Taken together, these results suggest the great potential of PEDOT:CNF composite for developing next-generation multifunctional microelectrodes for applications in neural therapies.

Biosensors for Epilepsy Management: State-of-Art and Future Aspects

Epilepsy is a serious neurological disorder which affects every aspect of patients’ life, including added socio-economic burden. Unfortunately, only a few suppressive medicines are available, and a complete cure for the disease has not been found yet. Excluding the effectiveness of available therapies, the timely detection and monitoring of epilepsy are of utmost priority for early remediation and prevention. Inability to detect underlying epileptic signatures at early stage causes serious damage to the central nervous system (CNS) and irreversible detrimental variations in the organ system. Therefore, development of a multi-task solving novel smart biosensing systems is urgently required. The present review highlights advancements in state-of-art biosensing technology investigated for epilepsy diseases diagnostics and progression monitoring or both together. State of art epilepsy biosensors are composed of nano-enabled smart sensing platform integrated with micro/electronics and display. These diagnostics systems provide bio-information needed to understand disease progression and therapy optimization timely. The associated challenges related to the development of an efficient epilepsy biosensor and vision considering future prospects are also discussed in this report. This review will serve as a guide platform to scholars for understanding and planning of future research aiming to develop a smart bio-sensing system to detect and monitor epilepsy for point-of-care (PoC) applications.

Interfaces with the peripheral nerve for the control of neuroprostheses

Nervous system injuries lead to loss of control of sensory, motor, and autonomic functions of the affected areas of the body. Provided the high amount of people worldwide suffering from these injuries and the impact on their everyday life, numerous and different neuroprostheses and hybrid bionic systems have been developed to restore or partially mimic the lost functions. A key point for usable neuroprostheses is the electrode that interfaces the nervous system and translates not only motor orders into electrical outputs that activate the prosthesis but is also able to transform sensory information detected by the machine into signals that are transmitted to the central nervous system. Nerve electrodes have been classified with regard to their invasiveness in extraneural, intraneural, and regenerative. The more invasive is the implant the more selectivity of interfacing can be reached. However, boosting invasiveness and selectivity may also heighten nerve damage. This chapter provides a general overview of nerve electrodes as well as the state-of-the-art of their biomedical applications in neuroprosthetic systems.

Conference Scene: Nanoneuroprotection and nanoneurotoxicity: recent progress and future perspectives

Recent developments in research related to nanoparticles in neuroscience necessitated the establishment of a new discipline known as ‘nanoneuroscience’. In order to understand the possible role of nanoparticles in the development of neurotoxicity or their potential use in neuroprotection, nine top experts across the world in this newly developing discipline were invited to present their cutting edge research in the 7th annual meeting of the Global College of Neuroprotection & Neuroregeneration in Stockholm, Sweden. The new developments suggest that more research is needed to understand the potential use of nanoparticles in nanomedicine. Highlights of these presentations are summarized in this article.